Members of Snohomish County PUD’s substation department recently participated in a five-day training course.
“Safety and reliability of our electrical equipment for our employees and customers is our main priority,” Matt Gregorich, Wireman Training Coordinator at the Washington State PUD told Public Power Current. Being a substation wireman at the PUD includes spending “an enormous amount of time and energy training on and testing of the equipment,” he said.
The training course consisted of three days of classroom electrical theory and two days of hands-on training.
“Our focus of the class is to test the power factor, and the insulation value of the equipment,” Gregorich said.
When testing substation class transformers, voltage transformers, bushings, dielectric mediums, windings, arrestors, load tap changers, deenergized tap changers, and many other types of equipment, “we have the manufacturer’s specified test result parameters that we need to follow.”
Most of the time “our equipment is reliable, but sometimes we get a bad actor. It is important for a substation wireman to recognize bad test results that point to a problem or a trend to a future problem that we can catch and fix now. Substation equipment is very expensive and hard to resource in a timely manner. A substation class transformer has a 3–5-year lead time,” he noted.
Some of the testing done in the training was to simulate damaged, broken, or contaminated insulators.
“We did this by comparing a good testing insulator to an insulator that was dirty, moldy, or covered with environmental contaminates such as salt water, which is highly conductive. We applied 10,000 volts to a compromised insulator and measured how much voltage was leaking past the insulation to the grounded conductor. If we can recognize the trends of a bad test result that will give us the confidence of the reliability and safety of our equipment,” Gregorich said.
The training took place at the Snohomish County PUD Substation Department’s Transformer Shop.
“The transformer shop is where we test, and accept new equipment, and also repair equipment that has been brought from the field.”
Some of the test equipment that is utilized is made by Doble, which offers 5 days of training on their test equipment annually.
“We take advantage of this service by setting up a testing laboratory to fully understand our equipment that has voltage ranges from 230 kv down to 48 volts DC,” Gregorich said.
“This was a lot of fun because mixing in various types of equipment that some were known to be defective and to have our wireman recognize and now know to perform multiple types of tests to verify that there is a problem,” he said.
“Snohomish County PUD has a lot of confidence in our wireman,” he said, adding that “they have ability to recognize a piece of equipment that is safe to stay in service for another 5-7 years or one that needs to be removed from service immediately.”
